You can set up call forwarding for your Grasshopper account phone using the Grasshopper website.
Log into your Grasshopper account:
Go to Settings > Call Forwarding Settings > Extensions
Click "Edit" next to the number or extension that you want Numa to answer if you can't.
Click "add a forwarding number" and enter your Numa number.
Select "Calls will connect as soon as you pick up" and customize it by hour, if you'd like. Then click "Add this Number."
Then, under option, decide how you want Grasshopper to ring the lines (if you have multiple lines). Since Numa will always pick up, in most cases you should select "In order, just once." If there are numbers that will ring before Numa in the list, click on "edit" by those numbers to control how long they will ring for.
Here is a video from Grasshopper showing the steps above:
How to Confirm It's Working
You can place a test call by going to Settings > Phone numbers > Test my setup or call your business's phone number from your personal phone. If nobody answers, you should hear your Numa Voicemail greeting.
Troubleshooting
Make sure you don't have an answering machine picking up your calls on any of your other extensions before they get forwarded.
Turn off Call Forwarding
Log back into your Grasshopper account and remove your Numa number.
No matter what, don't hesitate to contact Numa support! We'll happily work with you and your service provider to get you all set up.